In order to investigate whether Okazaki pieces initiate and/or terminate at defined sites on the genome, the genetic markers carried by Okazaki pieces will be assayed in a bacteriophage T4 DNA transformation system. The ability of the Okazaki pieces to cotransform closely spaced rII double mutants will be examined. A drop in cotransformation in a particular interval of the gene will be taken as evidence for a unique initiation/termination site in this interval. We also are investigating the properties of mutants of E. coli which carry external suppressors of the DNA genes. Comutagenesis with nitrosoguanidine and rapid mapping techniques are being used to screen likely suppressors. We are also investigating the properties of the DNA synthesis observed in toluene treated cells in the presence of the detergent Triton X-100. The DNA is being characterized by size on alkaline sucrose gradients, and genetic techniques are being used to identify the gene products necessary for such synthesis. BIBLIOGRAPHIC REFERENCES: Hanna, Michael H. and Philip L. Carl. Reinitiation of DNA Synthesis by Deoxyribonucleic Acid Initiation Mutants of Escherichia coli: Role of Ribonucleic Acid Synthesis, Protein Synthesis and Cell Division. J. Bact. 121:219 (1975). Hanna, Michael H., L. Stephanie Soucek and Philip L. Carl. Triton X-100 Dependent DNA Synthesis in an E. coli dnaC Mutant, in ICN-UCLA Symposia on Molecular and Cellular Biology, Volume III, in press (1975).